I didn't discuss Dark Matter because, as I understand it, it is not the predominant force at work in the Universe.

My personal opinion - Please don't take this personally, okay? :)

Even so it is Dark Matter which is the topic in this thread, not the most predominant force. If you thought it was more important then you should have added what you did as a side line and not the topic of the post/thread.

No offense taken. In my opinion my comments are related to this discussion, although, admittedly indirectly. The question is "Do you believe Dark Matter is real?" That is, Does one believe that something that cannot in any way be perceived is real?" The question pertains to Dark Energy as well in the sense that it is also something we cannot in any way perceive, but is postulated to exist to explain certain dynamics of how the Universe works.

Dark matter is about 83pct of the MATTER in the universe. Dark energy is about 72pct of the total MASS/ENERGY of the universe. Your top unlined phrase is how I understand it.

No scientist would use the terms interchangeable - they are completely different concepts; really only linked by their names.

Imat, you have explained a critical part of the definition I was misunderstanding. I.E. the "Matter" versus the "Mass/Energy". Looking back at the discussions, the scientists obviously are talking about one or the other of these two concepts, and not using them interchangeably.

Pete, I agree with you in that something must be done to give a explanation as to why galaxies have evolved and 'spin' as they do. And as it has to do with gravity and we don't find enough ordinary matter to explain it?

That is, Does one believe that something that cannot in any way be perceived is real?"

But Dark Matter is percieved. It interacts gravitationaly with all matter which has passive gravitational mass.

If it exists it may act gravitationally with all matter that has passive gravitational mass. It may not exist. It was formulated to explain an anomaly. It is not the only explanation and it is certainly not the simplest.

The link you gave gives practically no information but it does provide another link.http://www.space.com/11129-dark-energy-theory-universe-expansion.html"In a new study, a team of researchers led by Adam Riess of the Space Telescope Science Institute in Baltimore, report that they've calculated how fast the universe is expanding to a greater degree of accuracy than ever before, shrinking the error bars on their measurements by about 30 percent."

I believe that is meaningless gobbledygook based on a misconception. 30% of what? It is assumed it is a 30% improvement in in the measurement that the universe is 'expanding' in the SPACE dimension of space-time. There is absolutely no evidence that the expansion is in the SPACE dimension of space-time. What looks like an expansion in the SPACE dimension of space-time is just as likely to be a contraction in the TIME dimension of space-time. They both look identical. It's a 30% improvement in measurement but but you have to specify what the measurement refers to and in this case it is assumed that it refers to the SPACE in space-time. This is open to question as it could equally refer to the TIME in space-time. Time contraction is by far the simplest explanation as it requires nothing new. See reply #15 in this thread.

For all we know, the Universe could be contracting. If time is contracting fast enough then what looks like expansion could be contraction. As far as I am aware the only evidence for space expanding is in one way or another dependent upon the red-shift. As the red-shift has another and simpler explanation it is just insufficient evidence.

That is, Does one believe that something that cannot in any way be perceived is real?"

But Dark Matter is percieved. It interacts gravitationaly with all matter which has passive gravitational mass.

If it exists it may act gravitationally with all matter that has passive gravitational mass. It may not exist. It was formulated to explain an anomaly. It is not the only explanation and it is certainly not the simplest.

That's quite true. Have you studied this anomaly you mentioned here? How do you know that it s not the only explanation?

What you said is one reason why postulates can never be proven to be true. There are always other ways to explain observations. Scientists keep running tests to show that all other explainations fail to be true. When that happens a postulate becomes more believable. Consider for example, the following article

Quote

Anti-photon, W.E. Lamb, Appl. Phys, B 60, 77-84

Abstract. It should be apparent from the title of this article that the author does not like the use of the term "photon", which dates from 1926. In his view, there is no such thing as a photon. Only a comedy of errors and historical accidents led to its popularity among physicists and optical scientists. I admit that the word is short and convenient. Its use is also habit forming. Similarly, one might find it convenient to speak of the "aether" or "vacuum" to stand for empty space, even if no such thing existed. There are very good substitutes for "photon", (e.g. "radiation" or "light") and for "photonics" (e.g. "optics" or "quantum optics"). Similar objections are possible to use of the word "phonon", which dates from 1932. Objects like electrons, neutrinos of finite rest mass, or helium atoms can, under suitable conditions, be considered to be particles, since their theories then have a viable non-relativistic and non-quantum limits. This paper outlines the main features of the quantum theory of radiation and indicates how they can be used to treat problems in quantum optics.

For those of you who don't recognize the author, he won the Nobel Prize in physics in quantum electrodynamics!

No theory can ever be proven right and therefore what we believe to be true might actually be proven false. And for that reason there will always been room to say "Yeah but maybe someday a scientist might come up with an explanation which is consistent will all know observations but be conceivable with theory so and so so when we run a text to see if it's right we can have reason to doubt the theory.

As far as Dark Matter goes one has to have a good understanding the reasons for it and reasons why other reasons against it we have to keep an open mind.

Consider again the question asked: Do you believe dark matter is real?

Take notice that the question did not ask whether they knew that dark matter was real. To date it is an hypothesis, one that has not yet been substantiated.

I think dark energy is here to stay, at least for a while. You could assume that if we all (mass) were shrinking at the same rate that space accelerate/expands, then that might be an sufficient explanation for what we see. As for assuming different 'time rates' as 'a contraction in the TIME dimension of space-time.' I will presume that this is a expansion' of your own ideas, and to be perfectly honest I'm not even sure how to interpret it?

There is a lot of accelerating expansion going on out there as it seems.

I think that there is one scenario that has been hypothesized by physicists (E.g. touched on in Gravition and Spacetime 2nd Ed., Ohanian& Ruffini) but has not yet been touched on in this thread. Now my question is Are you certain that you don't believe in the existance of dark matter but that you're taking it out of context?

Consider one of the possible explanations that has been consistent for Dark Matter is black holes. Ask your self whether you believe in the existance in black holes and if so would you consider their existance to be a candidate for dark matter?

Now that you've considered this as a plausible explanation would you now consider the existance of Dark Matter to strong?

Hmm, is the question directed to me Pete? Or to Mike? Both maybe :)When it comes to dark matter I don't know, something is needed but what it should be?I'll wait a while with assuming anything I think. But I liked the idea with neutrinos myself, then again, they are supposed to travel freely in the galaxy and if the research mentioned didn't find any evidence?

"“The amount of mass that we derive matches very well with what we see -- stars, dust and gas -- in the region around the Sun,” says team leader Christian Moni Bidin (Departamento de Astronomia, Universidad de Concepcion, Chile). “But this leaves no room for the extra material -- dark matter -- that we were expecting. Our calculations show that it should have shown up very clearly in our measurements. But it was just not there!” "

So I can't really say what it should be. You have those mini black holes too? Maybe those could be it? I don't really know.

I think dark energy is here to stay, at least for a while. You could assume that if we all (mass) were shrinking at the same rate that space accelerate/expands, then that might be an sufficient explanation for what we see. As for assuming different 'time rates' as 'a contraction in the TIME dimension of space-time.' I will presume that this is a expansion' of your own ideas, and to be perfectly honest I'm not even sure how to interpret it?

There is a lot of accelerating expansion going on out there as it seems.

We understand from relativity that time is relative. That is not open to debate. We know that acceleration (which is gravity) affects the time dilation factor. That's not open to debate. If we believe in GR then we believe in space-time. Space-time has two components. Space and time. Acceleration has two components, the change in velocity over time. If either of the components changes then it represents acceleration. So acceleration can be a change in distance covered in space per unit time. It can equally be a change in time. The faster you travel in space, the less you travel in time. The faster you travel in time, the less you travel in space.

When time contracts each successive second is shorter than the proceeding one. Less photons arrive per second than in a previous second. Less wavelengths of light arrive per second than in a previous second. Less photons arriving per second can have two explanations. (1) Time is contracting. (2) Space is expanding. Less wavelengths of light arriving per second can have two explanations. (1) Time is contracting. (2) Space is expanding.

I am at a loss to understand what is open to debate about the above but I am more than happy to debate it.

I would just add 'time contraction' and 'space expansion' look EXACTLY the same. That may be open to debate but to the best of my knowledge is correct.

This one might be more useful to you Mike? it lists the ways ways astronomers, and others, use for deducing/finding a 'dark energy'. New evidence backs dark energy.

New approachProfessor Charlie Lineweaver, a cosmologist from the Australian National University, says this study demonstrates a new way to confirm the accelerated expansion of the universe.

"There are five ways to determine how fast the universe's expansion rate is accelerating," says Lineweaver.

"Schmidt used supernovae, which is still the most accurate method. There's also baryonic acoustic oscillations which are density waves that propagate through the universe, there's the cosmic microwave background radiation and you can also count the numbers of star clusters at given distances."

"Having the same conclusions reached by different methods is a tremendously important tool in any scientific research."

All that seems to confirm is the measured accuracy of the red-shift.My concern is that all of the above evidence relies upon the red-shift. The red-shift is the very thing that is open to debate. It's a circular argument. The red shift can have two explanations, time contraction or space expansion. As they look the same both would account for the above five points.

I think that there is one scenario that has been hypothesized by physicists (E.g. touched on in Gravition and Spacetime 2nd Ed., Ohanian& Ruffini) but has not yet been touched on in this thread. Now my question is Are you certain that you don't believe in the existance of dark matter but that you're taking it out of context?

Consider one of the possible explanations that has been consistent for Dark Matter is black holes. Ask your self whether you believe in the existance in black holes and if so would you consider their existance to be a candidate for dark matter?

Now that you've considered this as a plausible explanation would you now consider the existance of Dark Matter to strong?

I guess black holes could be considered by definition to be dark matter as we can't see them.However, that is not necessarily true. If matter continues to accelerate once inside the EH then it is going backward in time. If it is going backward in time then charge and parity have reversed, can it still be considered to be 'matter' or is it now 'antimatter'? In which case a black hole is not dark matter but dark antimatter. Something that is time reversed can not emit light. Reflected light is reflected into the past. Either way it cannot be seen, just like a black hole.

When I think of dark matter I think of what is required to account for the existence of galaxies in the way they are generally perceived. Black holes would do the job but it would require an awful lot of them and they would probably announce their existence in ways that we do no observe.

Rather than answer the question directly I would suggest it was the wrong question. Perhaps the question should have been. Why do we have to postulate the existence of dark matter as a means of answering a question in the presence of a simpler answer to that question? See explanation in reply 16 of this thread.

Science operates on a consensus of opinion amongst your peers. It owes little to what is actually true but as we seldom know what is true it is probably the best that we can expect.Unfortunately for the likes of me I have no peers to form a consensus.

MOD NOTE: Mike, as you've been told numerous times, the New Theories forum is the proper place to discuss your own theories. At most, please invite others to come to your New Theories thread for discussion. Moreover, if you want to criticize science as a whole for how it accepts new theories, please take it to another forum. TNS is a science Q&A forum, not a place to air grudges against science.

Science operates on a consensus of opinion amongst your peers. It owes little to what is actually true but as we seldom know what is true it is probably the best that we can expect.Unfortunately for the likes of me I have no peers to form a consensus.

All that is quite untrue. The reason science operates on a consensus of opinion amongst its peers is only because one has to learn so much on the topic of discussion that by the time they learn enough to do so they have become peers. It's similar to people who speak French. They only speak French with French speaking people because it's only French speaking people who can undersand them.

As far as It owes little to what is actually true... is also wrong but you'll never know that unless you become versed in the language of science. I myself spent years upon years spending most of my days learning physics, the philosophy of physics and language of physics (i.e. math) to become able to understand what I needed to know and that was only the basics to learn what I wanted to learn. For examle, it took me many years to understand tensor analysis just so that I could learn general relativity.

You could always learn to become a physicist by starting off with the basics (basic physics and math) and that will give you the basics to put yourself in the position to start to lean physics (since physics forum is where you keep posting from what I see). Warning: It's a very long road but it's worth the travel.

Science operates on a consensus of opinion amongst your peers. It owes little to what is actually true but as we seldom know what is true it is probably the best that we can expect.Unfortunately for the likes of me I have no peers to form a consensus.

You could always learn to become a physicist by starting off with the basics (basic physics and math) and that will give you the basics to put yourself in the position to start to lean physics (since physics forum is where you keep posting from what I see). Warning: It's a very long road but it's worth the travel.

You presume I have no formal training in physics or math. I would not be so presumptuous. If you wish to debate my ideas, even with a view to proving me wrong, I would be delighted but please do not adopt a condescending attitude toward me.

Mike and Pete - no more comments about the person, education, or perceived attitude please; we are dangerously close to the borders of acceptability so let's get back to substantive science before anyone goes too far.

Making an assumption about a persons training can't logically be considered condescending and making an assumption about such training says nothing about an assumption about their intelligence. In any case I think it'd be best for mt not to prticipate in discussions with people who are so offended.

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